Evaporator with grooved channels

ABSTRACT

An evaporator element is provided and includes a body defining channels, each of which includes grooves respectively delimited by first and second interior facing sidewalls of the body which form a base and an apex with an apex angle opposite the base and defined such that, for a fluid flow moving through one of the channels in a microgravity environment a portion of the fluid flow in a liquid phase within a groove of the channel will move in the groove from the base to the apex and a portion of the fluid flow in a vapor phase within a groove of the channel will move in the groove from the apex to the base.

BACKGROUND

The following description relates to evaporators and, more particularly,to an evaporator with grooved channels for terrestrial and microgravityenvironments.

Evaporators utilize latent heat of a fluid to absorb waste heat from aheat source. As such, in order to operate efficiently, an evaporatingsurface of an evaporator should be covered by a layer of a liquid phaseof a working fluid as much as possible during operational conditions.

The liquid phase of a working fluid (i.e., liquid) tends to accumulateand move in the direction of gravity in a terrestrial environment. In amicrogravity environment, liquid distribution is randomized and tends tomove freely if undisturbed. Therefore, in each of these terrestrial andmicrogravity environment cases, it is often critical to replenishevaporating surfaces of evaporators with liquid.

BRIEF DESCRIPTION

According to an aspect of the disclosure, an evaporator element isprovided and includes a body defining channels, each of which includesgrooves respectively delimited by first and second interior facingsidewalls of the body which form a base and an apex with an apex angleopposite the base and defined such that, for a fluid flow moving throughone of the channels in a microgravity environment a portion of the fluidflow in a liquid phase within a groove of the channel will move in thegroove from the base to the apex and a portion of the fluid flow in avapor phase within a groove of the channel will move in the groove fromthe apex to the base.

In accordance with additional or alternative embodiments, the channelsare arrayed in a linear formation.

In accordance with additional or alternative embodiments, each of thechannels has a same shape.

In accordance with additional or alternative embodiments, each of thegrooves is immediately adjacent to neighboring grooves.

In accordance with additional or alternative embodiments, each of thegrooves has a same shape.

In accordance with additional or alternative embodiments, the groovesare circumferentially arrayed to extend outwardly from an open centralregion.

In accordance with additional or alternative embodiments, the apex angleis 2β and β is less than 90° minus a solid-liquid contact angle.

According to an aspect of the disclosure, an evaporator element isprovided and includes a body defining channels, each of which includesgrooves respectively delimited by first and second interior facingsidewalls of the body which form an apex angle 2β, where β is less than90° minus a solid-liquid contact angle.

In accordance with additional or alternative embodiments, the channelsare arrayed in a linear formation.

In accordance with additional or alternative embodiments, each of thechannels has a same shape.

In accordance with additional or alternative embodiments, each of thegrooves is immediately adjacent to neighboring grooves.

In accordance with additional or alternative embodiments, each of thegrooves has a same shape.

In accordance with additional or alternative embodiments, the groovesare circumferentially arrayed to extend outwardly from an open centralregion.

According to an aspect of the disclosure, an evaporator is provided andincludes first and second headers and a body interposed between thefirst and second headers and defining channels to permit fluid flowbetween the first and second headers. Each channel includes groovesrespectively delimited by first and second interior facing sidewalls ofthe body which form a base and an apex with an apex angle opposite thebase and defined such that, for a fluid flow moving through one of thechannels in a microgravity environment a portion of the fluid flow in aliquid phase within a groove of the channel will move in the groove fromthe base to the apex and a portion of the fluid flow in a vapor phasewithin a groove of the channel will move in the groove from the apex tothe base.

In accordance with additional or alternative embodiments, the channelsare arrayed in a linear formation and each of the channels has a sameshape.

In accordance with additional or alternative embodiments, each of thegrooves is immediately adjacent to neighboring grooves and each of thegrooves has a same shape.

In accordance with additional or alternative embodiments, the groovesare circumferentially arrayed to extend outwardly from an open centralregion.

In accordance with additional or alternative embodiments, the apex angleis 2β, where β is less than 90° minus a solid-liquid contact angle.

In accordance with additional or alternative embodiments, orificeinserts are respectively interposable between one of the first andsecond headers and a corresponding channel.

In accordance with additional or alternative embodiments, each orificeinsert includes a center plug defining multiple inflow channels and aring feature disposed about the center plug and defining a plenum withwhich termination points of the multiple inflow channels are fluidlycommunicative.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter, which is regarded as the disclosure, is particularlypointed out and distinctly claimed in the claims at the conclusion ofthe specification. The foregoing and other features, and advantages ofthe disclosure are apparent from the following detailed descriptiontaken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of an evaporator element in accordance withembodiments;

FIG. 2 is a perspective view of a body and grooves channels of theevaporator element of FIG. 1 in accordance with embodiments;

FIG. 3 is an axial view illustrating a configuration of the grooves ofthe grooves channels of FIG. 2 in accordance with embodiments;

FIG. 4 is an illustration of an operation of the groove channels of FIG.2 in a microgravity environment in accordance with embodiments;

FIG. 5 is an illustration of an operation of the groove channels of FIG.2 in a gravity field in accordance with embodiments;

FIG. 6 is a perspective view of an orifice insert in accordance withembodiments;

FIG. 7 is a perspective view of the orifice insert of FIG. 6 inaccordance with embodiments;

FIG. 8 is a side view of an orifice insert of FIGS. 6 and 7 interposedbetween an inlet header and a channel in accordance with embodiments;

FIG. 9 is a perspective view of orifice inserts of FIGS. 6 and 7interposed between an inlet header and channels in accordance withembodiments;

FIG. 10 is a perspective view of orifice inserts of FIGS. 6 and 7 seatedin an external groove of an inlet header in accordance with embodiments;and

FIG. 11 is an axial view of an orifice insert and a grooved channel inthe background to illustrate movement of liquid through the orificeinsert in accordance with embodiments.

These and other advantages and features will become more apparent fromthe following description taken in conjunction with the drawings.

DETAILED DESCRIPTION

Movement of liquid in a microgravity environment is mainly dictated by asurface tension of the liquid, characteristics of a surface the liquidis intended to be in contact with and external disturbances applied tothe system. In a terrestrial environment, the liquid will tend to pooland flow in the direction of gravity. In either case, in a properlydesigned groove, liquid can be replenished into the groove and vapor canbe expelled out of the groove at similar rates which is useful in thereplenishment of liquid on an evaporating surface of an evaporator. Assuch, as will be described below, a groove geometry in which liquid canbe replenished into the groove and vapor can be expelled out of thegroove at similar rates in integrated into an evaporator design. Theevaporator design is therefore suitable for both terrestrial andmicrogravity environments.

With reference to FIGS. 1-3, an evaporator element 101 is provided andincludes a first header (hereinafter referred to as an “inlet header”)110, a second header (hereinafter referred to as an “outlet header”) 120and a body 130. The body 130 is formed to define channels 140 that maybe arranged in a linear formation 141 across a width W of the body 130.Each of the channels 140 can have a substantially same shape as theothers and includes grooves 142 that are circumferentially arrayed toextend radially outwardly from an open central region 143.

Each of the grooves 142 has a same shape as the others and isimmediately adjacent to neighboring grooves 142. In addition, each ofthe grooves 142 is delimited by first and second interior facingsidewalls 144 of the body 130. The first and second interior facingsidewalls 144 are tapered toward each other to form a base B and an apexA. The apex A is opposite the base B and has an apex angle 2β where β isless than 90° minus a solid-liquid contact angle. That is, the apexangle 2β is defined such that, for a fluid flow moving through one ofthe channels 140 in a microgravity environment where a portion of thefluid flow is in a liquid phase and another portion of the fluid flow isin a vapor phase, the portion of the fluid flow in the liquid phasewithin a particular groove 142 of the channel 140 will move in theparticular groove 142 from the base B to the apex A and the portion ofthe fluid flow in the vapor phase within the particular groove 142 willmove in the particular groove 142 from the apex A to the base B.

With reference to FIG. 4, an operation of the channels 140 and thegrooves 142 in a microgravity environment is illustrated. As shown inFIG. 4, in the microgravity environment, once liquid contacts the firstand second interior facing sidewalls 144 of each of the grooves 142, theliquid moves in the direction from the base B and to the apex A. Aftervaporization by exposure of the body 130 to heat, the vapor is expelledfrom the apex A toward the base B and to the open central region 143.

With reference to FIG. 5, an operation of the channels 140 and thegrooves 142 in a gravity field is illustrated. As shown in FIG. 5, dueto the influence of gravity, the liquid is mostly accumulated at thebottom portion of the channels 140. Nevertheless, since heat applied tothe body 130 can be conducted to the liquid, vaporization of the liquidis still possible.

With reference to FIGS. 6 and 7, an orifice insert 601 is provided andincludes a center plug 610 and a ring feature 620. The center plug 610has a first end 611, a second end 612 opposite the first end 611 and anexterior surface 613 that extends between the first and second ends 611and 612. The exterior surface 613 has a curved plane P and is formed todefine multiple inflow channels 630 that extend from the first end 611toward the second end 612 and that terminate at termination points 631defined midway between the first and second ends 611 and 612. Each ofthe multiple inflow channels 630 has a u-shaped cross-section 632 thatis directed inwardly from the curved plane P. The ring feature 620 isdisposed about the center plug 610 and the multiple inflow channels 630and includes an axial face 621 and a radial face 622. The axial face 621is adjacent to the center plug 610 and the multiple inflow channels 630.The radial face 622 is disposed at a distal edge of the axial face 621and is oriented to face radially inwardly toward the center plug 610 andthe multiple inflow channels 630. The ring feature 620 is thus disposedto define, with the center plug 610, a plenum 640 with which thetermination points 631 of the multiple inflow channels 630 are fluidlycommunicative. The plenum 640 extends circumferentially about the centerplug 610 and the multiple inflow channels 630. The multiple inflowchannels 630 thus extend beneath the ring feature 620 in a radialdimension. The termination points 631 are axially aligned with theplenum 640 and can be scalloped or otherwise configured to direct fluidflow moving along the multiple inflow channels 630 radially outwardlyand into the plenum 640.

The multiple inflow channels 630 are designed and configured to create adesired back pressure to achieve proper flow distribution among thechannels 140 in the body 130 (see FIGS. 1 and 2). Fluid moving along oneof the multiple inflow channels 630 flows from the first end 611 andtoward the second end 612. The fluid passes beneath the ring feature 620in a radial dimension and interacts with the corresponding terminationpoint 631. This interaction causes the fluid to enter the plenum 640 andto flow in a circumferential direction.

With reference back to FIG. 1 and with additional reference to FIGS.8-11, orifice inserts 601 are respectively interposable between theinlet header 110 and a corresponding channel 140 in the body 130 of theevaporator element 101 (se FIG. 1). As shown in FIGS. 9 and 10, theinlet header 110 includes a header body 901 that is formed to define acentral cavity 910 (see FIG. 8), apertures 920 for fluid communicationbetween the central cavity 910 and the channels 140 and an externalgroove 930. The orifice inserts 601 are respectively insertable intocorresponding ones of the apertures 920 and are seatable in the externalgroove 930 to respectively register with corresponding ones of thechannels 140. Where the corresponding channel 140 has the grooves 142 asdescribed above, the orifice insert 601 is disposed and configured toencourage fluid of the fluid flow from the inlet header 110 to thecorresponding channel 140 to flow into the grooves 142 of thecorresponding channel 140.

In an operation of the evaporator 101 with the orifice inserts 601respectively interposed between the inlet header 110 and correspondingchannels 140 in the body 130 of the evaporator element 101, liquidentering the inlet header 110 is distributed to each of the apertures1120 by the central cavity 1110. Once the liquid enters an aperture1120, the liquid is forced into the multiple inflow channels 630 andflows along the multiple inflow channels 630 to the termination points631. The termination points 631 redirect the liquid into the plenum 640whereupon the liquid is directed into the grooves 142 of the channels140.

Technical effects and benefits of the features described herein are theprovision of an evaporator with properly designed grooves that can beused in either terrestrial or microgravity environments. In microgravityenvironments, the grooves are capable of replenishing liquid toevaporating surfaces that ensure the evaporator operation is proper andefficient. In addition to this self-wetting capability, the addition ofthe groove surface areas increases the evaporative surface area andimproves the evaporator performance in both the terrestrial and themicrogravity environments.

While the disclosure is provided in detail in connection with only alimited number of embodiments, it should be readily understood that thedisclosure is not limited to such disclosed embodiments. Rather, thedisclosure can be modified to incorporate any number of variations,alterations, substitutions or equivalent arrangements not heretoforedescribed, but which are commensurate with the spirit and scope of thedisclosure. Additionally, while various embodiments of the disclosurehave been described, it is to be understood that the exemplaryembodiment(s) may include only some of the described exemplary aspects.Accordingly, the disclosure is not to be seen as limited by theforegoing description, but is only limited by the scope of the appendedclaims.

What is claimed is:
 1. An evaporator element, comprising: a bodydefining channels, each of which comprises grooves respectivelydelimited by first and second interior facing sidewalls of the bodywhich form a base and an apex with an apex angle opposite the base anddefined such that, for a fluid flow moving through one of the channelsin a microgravity environment: a portion of the fluid flow in a liquidphase within a groove of the channel will move in the groove from thebase to the apex, and a portion of the fluid flow in a vapor phasewithin a groove of the channel will move in the groove from the apex tothe base.
 2. The evaporator element according to claim 1, wherein thechannels are arrayed in a linear formation.
 3. The evaporator elementaccording to claim 1, wherein each of the channels has a same shape. 4.The evaporator element according to claim 1, wherein each of the groovesis immediately adjacent to neighboring grooves.
 5. The evaporatorelement according to claim 1, wherein each of the grooves has a sameshape.
 6. The evaporator element according to claim 1, wherein thegrooves are circumferentially arrayed to extend outwardly from an opencentral region.
 7. The evaporator element according to claim 1, whereinthe apex angle is 2β and β is less than 90° minus a solid-liquid contactangle.
 8. An evaporator element comprising a body defining channels,each of which comprises grooves respectively delimited by first andsecond interior facing sidewalls of the body which form an apex angle2β, where β is less than 90° minus a solid-liquid contact angle.
 9. Theevaporator element according to claim 8, wherein the channels arearrayed in a linear formation.
 10. The evaporator element according toclaim 8, wherein each of the channels has a same shape.
 11. Theevaporator element according to claim 8, wherein each of the grooves isimmediately adjacent to neighboring grooves.
 12. The evaporator elementaccording to claim 8, wherein each of the grooves has a same shape. 13.The evaporator element according to claim 8, wherein the grooves arecircumferentially arrayed to extend outwardly from an open centralregion.
 14. An evaporator, comprising: first and second headers; and abody interposed between the first and second headers and definingchannels to permit fluid flow between the first and second headers, eachchannel comprising grooves respectively delimited by first and secondinterior facing sidewalls of the body which form a base and an apex withan apex angle opposite the base and defined such that, for a fluid flowmoving through one of the channels in a microgravity environment: aportion of the fluid flow in a liquid phase within a groove of thechannel will move in the groove from the base to the apex, and a portionof the fluid flow in a vapor phase within a groove of the channel willmove in the groove from the apex to the base.
 15. The evaporatoraccording to claim 14, wherein the channels are arrayed in a linearformation and each of the channels has a same shape.
 16. The evaporatoraccording to claim 14, wherein each of the grooves is immediatelyadjacent to neighboring grooves and each of the grooves has a sameshape.
 17. The evaporator according to claim 14, wherein the grooves arecircumferentially arrayed to extend outwardly from an open centralregion.
 18. The evaporator according to claim 14, wherein the apex angleis 2β, where β is less than 90° minus a solid-liquid contact angle. 19.The evaporator according to claim 14, further comprising orifice insertsrespectively interposable between one of the first and second headersand a corresponding channel.
 20. The evaporator according to claim 19,wherein each orifice insert comprises: a center plug defining multipleinflow channels; and a ring feature disposed about the center plug anddefining a plenum with which termination points of the multiple inflowchannels are fluidly communicative.